package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@RequiredArgsConstructor
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    private final ISeckillVoucherService seckillVoucherService;
    private final RedisIdWorker redisIdWorker;
    private final StringRedisTemplate stringRedisTemplate;
    private final RedissonClient redissonClient;
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();
//    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    private IVoucherOrderService proxy;
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private class VoucherOrderHandler implements Runnable {
        String queueName = "stream.orders";
        @Override
        public void run() {
            while (true) {
                try {
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    if (list == null || list.isEmpty()) {
                        continue;
                    }
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    handleVoucherOrder(voucherOrder);
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while(true) {
                try {
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    if (list == null || list.isEmpty()) {
                        break;
                    }
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    try {
                        Thread.sleep(200);
                    } catch (InterruptedException ex) {
                        throw new RuntimeException(ex);
                    }
                }
            }
        }
    }

    /**
     * 一下是通过阻塞队列，并非使用消息队列完成的异步操作
     */
/*    private class VoucherOrderHandler implements Runnable {
        @Override
        public void run() {
            while (true) {
                try {
                    VoucherOrder voucherOrder = orderTasks.take();
                    handleVoucherOrder(voucherOrder);
                } catch (InterruptedException e) {
                    log.error("处理订单异常", e);
                }
            }
        }
    }*/




    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        //创建锁
//        SimpleRedisLock lock = new SimpleRedisLock(stringRedisTemplate, "order:" + userId);
        Long userId = voucherOrder.getUserId();
        RLock lock = redissonClient.getLock(RedisConstants.LOCK_ORDER_KEY + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        //无法获取
        if (!isLock) {
            log.error("无法获取锁");
        }
        //能够获取
        try {
            //获取代理对象（事务）
            proxy.createVoucherOrder(voucherOrder);
        } catch (IllegalStateException e) {
            throw new RuntimeException(e);
        } finally {
            lock.unlock();
        }
    }

    @Override
    public Result seckillVoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        long orderId = redisIdWorker.nextId("order");
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString(),
                String.valueOf(orderId)
        );
        int r = result.intValue();
        if (r != 0) {
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        return Result.ok(orderId);
    }


/*    @Override
    public Result seckillVoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString()
        );
        int r = result.intValue();
        if (r != 0) {
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        VoucherOrder voucherOrder = new VoucherOrder();
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        voucherOrder.setUserId(userId);
        voucherOrder.setVoucherId(voucherId);
        orderTasks.add(voucherOrder);
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        return Result.ok(orderId);
    }*/

/*    @Override
    public Result seckillVoucher(Long voucherId) {
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        LocalDateTime now = LocalDateTime.now();
        if (now.isBefore(voucher.getBeginTime())) {
            return Result.fail("秒杀尚未开始");
        }
        if (now.isAfter(voucher.getEndTime())) {
            return Result.fail("秒杀已经结束");
        }
        if (voucher.getStock() < 1) {
            return Result.fail("库存不足");
        }
        Long userId = UserHolder.getUser().getId();
        //创建锁
//        SimpleRedisLock lock = new SimpleRedisLock(stringRedisTemplate, "order:" + userId);
        RLock lock = redissonClient.getLock(RedisConstants.LOCK_ORDER_KEY + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        //无法获取
        if (!isLock) {
            return Result.fail("不允许重复下单");
        }
        //能够获取
        try {
            //获取代理对象（事务）
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } catch (IllegalStateException e) {
            throw new RuntimeException(e);
        } finally {
            lock.unlock();
        }

    }*/

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        if (count > 0) {
            log.error("用户已经购买过了");
        }
        boolean success = seckillVoucherService.update().setSql("stock = stock - 1")
                .eq("voucher_id", voucherOrder.getVoucherId())
                //乐观锁
                .gt("stock", 0)
                .update();
        if (!success) {
            log.error("库存不足");
        }
        save(voucherOrder);
    }
}
